Bag for vacuum sealing and material for the bag

ABSTRACT

A bag for vacuum sealing which has a bag body composed of a first sheet  11  and a second sheet  12,  which have thermally fusible synthetic resin films  11   a  and  12   a  on at least the respective inner surfaces, and a non-woven fabric  15  which is a gas-permeable fiber structure formed of thermally fusible fibers. The sheets  11  and  12  are thermally fused together at both sides a and a lower side b, and the unfused upper side becomes an open side  13  of the bag body. The non-woven fabric  15  is bonded or fused with the inner surface of either one of the sheets  11  and  12.  Food, clothing or the like is put in a space  16  between the sheet and the non-woven fabric  15,  and air is extracted from the interior of the bag body through the open side  13.  The open side  13  is thermally sealed in the portion with a width between “c” and “c”. During the air extraction, near the open side  13,  the air inside the bag body is sucked through the non-woven fabric  15  in a direction perpendicular to the thickness of the fabric  15.  For the thermal sealing of the open side  13,  the fibers of the non-woven fabric  15  at the portion  13  are melted and fused with the sheets  11  and  12.  Instead of the non-woven fabric  15,  a finished fabric or a woven cloth may be used, and such a fabric or cloth may not be bonded or fused with the inner surfaces of the sheets  11  and  12.

TECHNICAL FIELD

[0001] The present invention relates to a bag for vacuum sealing and a material for the bag, and more particularly to a bag which is used for vacuum packaging of food for refrigeration thereof or for vacuum packaging of bedding and clothing for space-saving storage thereof, and a material for the bag.

BACKGROUND ART

[0002] When food such as meat, fish or the like is to be stored in a refrigerator, conventionally, the food is put in a bag made of a synthetic resin film, and air is extracted form the interior of the bag. Then, the bag is sealed so that the food inside the bag will not contact with oxygen. Not only such bags but also devices which perform thermal sealing of the opening of the bag simultaneously with extraction of air from the interior of the bag have been provided.

[0003] A bag which is described in U.S. Pat. No. Re. 34,929 has been known as a bag for vacuum sealing. As FIG. 8 shows, a synthetic resin film 1 which has islands 2 and channels 3 on its entire surface is used to make this bag. After food is contained in the bag, air is extracted from the interior of the bag through an open end using the channels 3 as air passages. After the extraction of air, the open end is thermally sealed so as to close the bag.

[0004] The bag, however, has the following disadvantages. In order to maintain the shapes of the islands 2 and the channels 3, the film 1 is required to have sufficient stiffness and thickness. For this purpose, a thick polyethylene terephthalate film or a polyamide film is used as the film 1, which raises the cost. Also, the item contained in the bag does not stick to the inner surface of the bag sufficiently during the air extraction. Further, because the film 1 is not absorbent, during the air extraction, water of the item contained in the bag (for example, meat juice) may flow into a sucking device through the channels 3, and the water may remain in the sealing position, which prevents the portion from being securely sealed.

[0005] An object of the present invention is to provide a bag for vacuum sealing which is absorbent, which sufficiently sticks to an item contained therein and which can be produced at low cost, and a material for the bag.

DISCLOSURE OF INVENTION

[0006] In order to attain the object, a bag for vacuum sealing according to the present invention comprises a bag body formed of a first sheet and a second sheet, each of which has a thermally fusible synthetic resin film on at least an inner surface, and a non-woven fabric, a finished fabric or a woven cloth which is a gas-permeable fiber structure formed of thermally fusible synthetic fibers. The bag body has three closed sides and one open side, and the non-woven fabric, the finished fabric or the woven cloth is located between the first sheet and the second sheet. Air is extracted from the interior of the bag body through the open side, and at this time, the air in the bag body is sucked through the non-woven fabric, the finished fabric or the woven cloth in a direction perpendicular to the thickness of the fabric or cloth. After the air extraction, the open side is heated, and thereby, at the heated portion, the fibers of the non-woven fabric, the finished fabric or the woven cloth are melted and fused with the inner surfaces of the first and the second sheets of the bag body, so that the open side is closed.

[0007] The bag according to the present invention uses the spaces among fibers of the non-woven fabric, the finished fabric or the woven cloth which is provided in the bag body as air passages. Air inside the bag body is sucked through the surface of the non-woven fabric, the finished fabric or the woven cloth, and in a portion near the open side, air is sucked in a direction perpendicular to the thickness of the fabric or cloth. Then, after the air extraction, the open side is heated, and thereby, at the heated portion, the fibers of the non-woven fabric, the finished fabric or the woven cloth are melted and fused with the inner surfaces of the first and the second sheets of the bag body, so that the open side is closed.

[0008] The bag according to the present invention has a non-woven fabric, a finished fabric or a woven cloth inside and accordingly absorbs water. The possibility that during air extraction, water of an item contained in the bag may flow into a sucking device can be reduced. Moreover, the non-woven fabric, the finished fabric or the woven cloth has a shock-absorbing characteristic and is soft toward the item in the bag, and thereby the item in the bag can be preserved longer. Further, it is not necessary to carry out an emboss treatment of the first and second sheets, and polyethylene films and polyethylen terephthalate films, which are thin, soft and inexpensive, are usable. Because of the softness of the sheets, the sheets are sticky to the item contained in the bag.

[0009] In addition, the non-woven fabrics, before sealing, are seen opaque because of diffusion on the fibers, while after sealing, the fibers at the heated and sealed portion are melted and seen transparent. Thereby, it is possible to recognize easily whether or not sealing has been carried out completely.

[0010] According to the present invention, a single non-woven fabric, finished fabric or woven cloth may be provided in the bag body, or two non-woven fabrics, finished fabrics or woven cloths may be provided. The non-woven fabric(s), finished fabric(s) or woven cloth(s) either may be bonded or fused with the inner surface(s) of the first sheet and/or the second sheet or may not be bonded or fused with the inner surface(s). In the latter case, food or clothing, etc. can be contained in the spaces among the sheets and the non-woven fabric(s), finished fabric(s) or woven cloth(s), and the bag has at least two separate rooms.

[0011] A material for the bag according to the present invention comprises a long stack of a first sheet and a second sheet, each of which has a thermally fusible synthetic resin film on at least an inner surface, and a non-woven fabric, a finished fabric or a woven cloth which is made of thermally fusible synthetic fibers. The first sheet and the second sheet are fused together at both sides along their length direction, and the non-woven fabric, the finished fabric or the woven cloth is located between the first sheet and the second sheet.

[0012] By sealing one end of the material by heat and by cutting a piece of a desired length out of the material, the above-described bag can be obtained. Food, clothing or the like is put in this bag, and thereafter, air is extracted from the interior of the bag. Then, the bag is sealed. The material according to the present invention is long, and the user can cut a piece of a desirable length out of the material.

BRIEF DESCRIPTION OF DRAWINGS

[0013]FIG. 1 shows a bag for vacuum sealing which is a first embodiment of the present invention, (A) being a front view and (B) being a fragmentary sectional view of a part.

[0014]FIG. 2 is a fragmentary sectional view of a bag for vacuum sealing which is a second embodiment of the present invention.

[0015]FIG. 3 is a fragmentary sectional view of a bag for vacuum sealing which is a third embodiment of the present invention.

[0016]FIG. 4 is a fragmentary sectional view of a bag for vacuum sealing which is a fourth embodiment of the present invention.

[0017]FIG. 5 is a perspective view which shows air extraction and sealing of a bag by use of an exemplary sucking/sealing device.

[0018]FIG. 6 is a sectional view of the principle part of the sucking/sealing device and the bag.

[0019]FIG. 7 is a front view of a material for a bag according to the present invention.

[0020]FIG. 8 is a perspective view of a synthetic resin film which is used to make a bag for vacuum sealing in a prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] In the following, some embodiments of a bag for vacuum sealing and a material therefor according to the present invention will be described with reference to the accompanying drawings.

First Embodiment of Bag for Vacuum Sealing; See FIG. 1

[0022] FIGS. 1(A) and 1(B) show a bag 10A which is a first embodiment of the present invention. As FIGS. 1(A) and 1(B) show, non-woven fabrics 15 are bonded or fused on the respective inner surfaces of two sheets 11 and 12, and the sheets 11 and 12 are thermally fused together at sides a and the lower side b, whereby the sides a and b are closed. The upper side is left open to be an opening 13.

[0023] The sheets 11 and 12 are laminated sheets. The sheets 11 and 12 have thermally fusible synthetic resin films (for example, polyethylene films) 11 a and 12 a on their respective inner surfaces and gas-impermeable synthetic resin films 11 b and 12 b (for example, polyethylene terephthalate films) on their respective outer surfaces.

[0024] The non-woven fabrics 15 are gas-permeable fiber structures formed of thermally fusible synthetic fibers. These non-woven fabrics 15 are bonded on the respective inner surfaces of the sheets 11 and 12. Alternatively, while the films 11 a and 12 a of the sheets 11 and 12 are melted, these non-woven fabrics 15 are placed on the films 11 a and 12 a so as to be fused with the films 11 a and 12 a respectively.

[0025] The sheets 11 and 12 and the non-woven fabrics 15 are of the same size, and the laminate of the sheet 11 and the non-woven fabric 15 and the laminate of the sheet 12 and the non-woven fabric 15 are fused together at the portions a and b.

[0026] Air extraction from the interior of the bag 10A and sealing of the opening 13 are simultaneously carried out by use of a device 20, of which example is shown in FIGS. 5 and 6. More specifically, after food, clothing or the like is put in the space between the non-woven fabrics 15, the open side 13 is put in the sucking/sealing device 20. The air inside the bag 10A is sucked out through the opening 13, and thereafter thermal sealing is carried out at the portion between the lines “c” and “c” shown in FIG. 1.

[0027] The air extraction and sealing by use of the device 20 will be described in detail later with reference to FIGS. 5 and 6.

[0028] Conventionally, it is well known that non-woven fabrics such as the fabrics 15 have gas permeability through spaces among the fibers in the thickness directions of the respective fabrics. According to the present invention, however, around the open side 13, air flows through the spaces among the fibers in a direction perpendicular to the thickness direction of the non-woven fabrics 15. After the air extraction from the interior of the bag 10A, the non-woven fabrics 15 are heated at the open side 13, whereby the fibers at the heated portion are melted. Thereby, the opening 13 is sealed.

[0029] In the bag 10A, thus, the non-woven fabrics 15 serve as air passages for air extraction. Also, the non-woven fabrics 15 are absorbent, and the possibility that water of the item contained in the bag 10A may flow to the sucking/sealing device during air extraction is much reduced. Moreover, the non-woven fabrics 15 have shock-absorbing characteristics and are soft toward the item in the bag 10A, and thereby, the item in the bag 10A can be preserved longer. Further, it is not necessary to carry out an emboss treatment of the sheets 11 and 12, and polyethylene films and polyethylen terephthalate films, which are thin, soft and inexpensive, are usable. Because of the softness of the sheets 11 and 12, the sheets 11 and 12 are sticky to the item contained in the bag 10A.

[0030] Further, the non-woven fabrics 15, before sealing, are seen opaque because of diffusion on the fibers, while after sealing, the fibers at the heated and sealed portion are melted and seen transparent. Thus, it is clearly distinguishable whether sealing has been done completely.

[0031] After the sealed portion is cut so as to open the bag 10A again, it is possible to remove air from the interior of the bag 10A through the newly formed opening and thereafter to thermally seal the bag 10A. Thus, reuse of the bag 10A is possible.

Second Embodiment of Bag for Vacuum Sealing; See FIG. 2

[0032] FIGS. 2 shows a bag 10B which is a second embodiment of the present invention. This bag 10B has a single non-woven fabric 15 between sheets 11 and 12. This non-woven fabric 15 is bonded or fused with the inner surface of the sheet 12 and is not bonded or fused with the inner surface of the sheet 11. An item is contained in the space between the sheet 11 and the non-woven fabric 15.

[0033] In the bag 10B, the structure of the sheets 11 and 12 and the plane structure of the bag 10B itself are the same as those of the bag 10A shown by FIG. 1, and the bag 10B functions in the same way and has the same advantages as the bag 10A of the first embodiment does. In the second embodiment, in addition, the item contained in the space 16 can be seen clearly through the transparent sheet 11.

Third Embodiment of Bag for Vacuum Sealing; See FIG. 3

[0034]FIG. 3 shows a bag 10C which is a third embodiment of the present invention. The bag 10C has a single non-woven fabric 15 between sheets 11 and 12, and this non-woven fabric 15 is not bonded or fused with neither the inner surface of the sheet 11 nor the inner surface of the sheet 12. Therefore, two spaces 16 are formed among the sheets 11, 12 and the non-woven fabric 15, and items can be contained in these two spaces 16.

[0035] In the bag 10C, the structure of the sheets 11 and 12 and the plane structure of the bag 10C itself are the same as those of the bag 10A shown by FIG. 1, and the bag 10C functions in the same way and has the same advantages as the bag 10A of the first embodiment does. In this third embodiment, in addition, because of the existence of the two spaces 16, different kinds of food can be contained separately in the bag 10C. Also, food may be put in one of the spaces 16, while a preservative, a deoxidizer or an absorbent may be put in the other space 16.

Fourth Embodiment of Bag for Vacuum Sealing; See FIG. 4

[0036]FIG. 4 shows a bag 10D which is a fourth embodiment of the present invention. This bag 10D has two non-woven fabrics 15 between sheets 11 and 12. These non-woven fabrics 15 are not bonded or fused with neither the inner surface of the sheet 11 nor the inner surface of the sheet 12. Therefore, three spaces 16 are formed among the sheets 11, 12 and the non-woven fabrics 15, and one or more items are contained in one, two or all of these spaces 16.

[0037] In the bag 10D, the structure of the sheets 11 and 12 and the plane structure of the bag 10D itself are the same as those of the bag 10A shown by FIG. 1, and the bag 10D functions in the same way and has the same advantages as the bag 10A of the first embodiment does. In this fourth embodiment, in addition, because of the existence of the three spaces 16, different kinds of food can be contained separately in the bag 10D. Also, food may be put in one or two of the spaces 16, while a preservative, a deoxidizer or an absorbent may be put in the other space 16.

Sucking/Sealing Device and the Usage Thereof; See FIGS. 5 and 6

[0038]FIGS. 5 and 6 show an example of a sucking/sealing device which is suited for the bags 10A through 10D and the usage of the device. In the following, a case of air extraction and sealing of the bag 10B of the second embodiment is described as an example.

[0039] The sucking/sealing device 20 has a sucking box 22 and a thermal sealing member 25 on a base plate 21 and further has a sucking pump 29 in the rear of the sucking box 22.

[0040] The sucking box 22 is composed of a lower box 22 a and an upper box 22 b. The lower box 22 a is fixed on the base plate 21, and the upper box 22 b pivots on a shaft 23 so as to open and close the lower box 22 a. While the lower box 22 b is closed by the upper box 22 a, the inside of the sucking box 22 is kept airtight. At the respective openable sides of the boxes 22 a and 22 b, rubbers 24 a and 24 b (see FIG. 6) are fitted so that the open side 13 of the vacuum bag 10B can be nipped between the rubbers 24 a and 24 b.

[0041] The thermal sealing member 25 is composed of a heating bar 27 and a rest 26. The rest 26 is fixed on the base plate 21 via a cushion 26 a, and the heating bar 27 is capable of moving up and down together with the upper box 22 b. On the lower side of the heating bar 27, heat chips 27 a which are heated by a heater (not shown) are provided.

[0042] Described in the following is a case of extracting air from the interior of the bag 10B containing an item 30 and sealing the bag 10B by use of the device 20 of the above-described structure.

[0043] First, while the sucking box 22 and the thermal sealing member 25 are opened, a portion of the bag 10B near the opening 13 is placed on the rubber 24 a and the rest 26. Then, the sucking box 22 and the thermal sealing member 25 are closed, and a suction switch (not shown) is turned on. Thereby, the sucking pump 29 starts operating to suck the air out of the bag 10B. During this sucking process, the portion of the bag 10B near the opening 13 is nipped with such a pressure not to close the spaces among the fibers of the non-woven fabric 15, and the air is sucked up through the spaces among the fibers. During this sucking process, thus, the non-woven fabric 15 serves as an air sucking passage. In the portion near the opening 13, the air inside the bag 10B is sucked into the non-woven fabric 15, and the air is sucked in the direction perpendicular to the thickness of the fabric 15 (the direction shown by arrow “A” in FIG. 6).

[0044] After the sucking process, a heat sealing switch (not shown) is turned on. Thereby, the heat chips 27 a of the heating bar 27 are electrified, and thermal sealing of the opening 13 is carried out. More specifically, the fibers of the non-woven fabric 15 are melted by heat and fused with the thermal fusible films 11 a and 12 a, so that the opening 13 is closed.

Embodiment of Material; See FIG. 7

[0045]FIG. 7 shows an embodiment of a material for a vacuum bag according to the present invention. The material 10′ is a long stack of the sheet 11, the non-woven fabric 15 and the sheet 12, and the sheets 11 and 12 and the fabric 15 are fused together by heat at both sides a.

[0046] A bag with a desired size can be cut out from this material 10′ by thermally sealing the lower side b by use of the thermal sealing member 25 of the sucking/sealing device 20. As has been described in connection with the bags 10A, 10B 10C and 10D, food, clothing or the like is contained in the bag, and thereafter, air is extracted from the interior of the bag. Then, the bag is sealed.

[0047] The material 10′ is supplied to each user in the form of a roll of a specified length. For actual use of a bag, the user cuts a desirable length from the roll.

[0048] The sectional structure of the material 10′ may be either one of FIGS. 1(B), 2, 3 and 4 or may be any other structure.

Other Embodiments

[0049] Although preferred embodiments of the present invention have been described above, it is to be noted various changes and modifications are possible to those who are skilled in the art. Sych changes and modifications are to be understood as being within the scope of the present invention.

[0050] For the sheets 11 and 12, various kinds of films as well as polyethylene and polyethylene terephthalate can be used. Also, these sheets 11 and 12 are not necessarily laminate sheets but may be made of a single film.

[0051] It is possible to use a finished fabric or a woven cloth instead of the non-woven fabric 15, and in these cases, also, the same effect can be obtained.

[0052] Further, various types of sucking/sealing devices as well as that shown by FIGS. 5 and 6 can be used.

Industrial Applicability

[0053] As has been described, bags for vacuum sealing and materials for these bags according to the present invention are suited to contain food and clothing, etc. Food can be preserved long in such a bag, oxidization and deterioration of the food being prevented. Clothing can be stored compactly in such a bag. 

1. A bag for vacuum sealing, comprising: a bag body comprising a first sheet and a second sheet, each of which has a thermally fusible synthetic resin film on at least an inner surface; and a non-woven fabric, a finished fabric or a woven cloth which is a gas-permeable fiber structure formed of thermally fusible synthetic fibers, wherein: the bag body has three closed sides and one open side; the non-woven fabric, the finished fabric or the woven cloth is located between the first sheet and the second sheet; when air is extracted from an interior of the bag body through the open side, the air in the bag body is sucked through the non-woven fabric, the finished fabric or the woven cloth in a direction perpendicular to a thickness of the non-woven fabric, the finished fabric or the woven cloth; after air extraction from the interior of the bag body, the open side is heated so that the fibers, at the open side, of the non-woven fabric, the finished fabric or the woven cloth are melted, whereby the open side is closed.
 2. A material for a bag according to claim 1, the material comprising: a long stack of a first sheet and a second sheet, each of which has a thermally fusible synthetic resin film on at least an inner surface; and a non-woven fabric, a finished fabric or a woven cloth which is a gas-permeable fiber structure formed of thermally fusible synthetic fibers, wherein: the first and second sheets are fused together at both sides along a length direction; and the non-woven fabric, the finished fabric or the woven cloth is located between the first sheet and the second sheet. 